4 Formula Littla

Let the system is in a steady condition (fig. 4 see). We will enter following designations:

- rate of receipt of calls;

- An average waiting time;

- Average of expecting calls.

Then we will receive the basic parity which is called as the formula of Littla: formula (3)

The equation (3) is interpreted as follows: as there is average time of stay of a call in turn this size can be taken into consideration as average time of deduction of expecting call in turn. At the same time the right party of this equation represents transport loading of expecting call which is equal to average of expecting calls according to property of 4 loadings on a theme 2.1 Modules 2. Can be noticed that there is an average size which will be noticed by extreme observers, and time interval W is defined experimentally on one skilled проходке turns.

System time is defined as the general time of stay (a waiting time + a holding time), spent by a call. Having designated average system time a symbol, and average of the calls existing (expecting + served) in system a symbol, we will receive a variant of the formula of Littla: formula (4)

The formula of Littla is applicable to any systems G/G/s, despite entrance process, the service mechanism and discipline of service of turn.

5 Transport loading

The new technics generates new terms, enriching and developing the Belarus language. In an electronic society has appeared кастомер. Кастомер occurs from an English word customer - кáстёмё - the customer, the client, the buyer. However actually кастомер both the businessman, and the founder, and the founder in the virtual Universe, capable to create, make, deliver, buy and sell софтвер and хардвер under individual orders of the consumer. And all it is carried out with use of a telecommunication service, including and fulfilment of transactions with use of electronic settlement-cash operations. Want to have such client? The client capable to create own virtual networks and to attach to them own subscribers, using resources of a network of telecommunication and by that, providing you an additional gain? Want? Then forward and directly! Study the theory of distribution of the information. Get the recommended textbook, use it as the reference book.

The call is defined as the requirement кастомера on a connection establishment in telecommunication system.

Deduction time (a holding time and-or service time) is defined as duration of a call.

Transport loading is defined as the general time of deduction in unit of time. Unit of transport loading is erlang (erl) in honour of the founder of the theory of the teletraffic A.K.Erlanga.

Let's consider an example. We will assume that on СМО(Система массового обслуживания –Queuing System) 3 calls at an o'clock in due course deduction, accordingly, 5, 10 and 15 minutes (fig. 5 see) have arrived. From here transport loading is calculated as…

Transport loading sometimes was called as intensity of loading and possesses following properties:

1) Let c will be quantity of calls (number of the calls generated in unit of time), and h average time of deduction. Then transport loading is set as a = c × h, [erl]. (5)

2) Transport loading equals to quantity of the calls generated during average time of deduction.

3) The Transport loading switched by a simple line, is equivalent to probability (time share) that the line is used (is occupied).

4) The Transport loading switched by a bunch of lines, is equivalent to an average (expected) number of the occupied lines in a bunch.

Properties 1-3 follow simply from definition of transport loading. Property 4 can be interpreted as follows. We will assume that полнодоступный the bunch from s lines switches transport loading an erl. Then the loading switched at the rate on one line, on the average is defined as a1 = (a/s) erl. And this loading owing to Property 3 is equivalent to probability of that the simple line is occupied. From here the average (expected) number of the occupied lines in a bunch is set by product of total number of lines in a bunch and the specified probability, i.e. s a₁ = a.